Vitamins support normal growth, development and cell functions. All B vitamins help convert carbohydrates into a source of energy (glucose). They assist in the formation of red blood cells.
It is thought that B vitamins may affect depression in these ways:
There is very little scientific evidence on vitamin B6 and B12 for the treatment of depression. More studies of better quality are needed.
Some studies found that adding folate (B9) to antidepressant medication was helpful. One trial found folate (B9) was most helpful for people whose symptoms had not fully responded to medication. Folate (B9) as a standalone treatment does not appear to reduce depression symptoms.
Some vitamin supplements can be harmful or ineffective if you take the wrong dose. For example, large doses of Vitamin B6 can cause nerve damage. Talk to your health care professional if you are thinking of taking supplements.
One study reported mania symptoms in a participant who was taking folate (B9) (and antidepressants). No other studies of B vitamins and depression have reported side effects. However, it is not clear whether the studies have investigated negative effects. More research is needed on the possible side effects of B vitamins.
Vitamins are present naturally in food. You can buy vitamin supplements in health food shops, supermarkets or from chemists. They usually come in tablet, capsule or powder form. Vitamins may also be given as an injection by a doctor.
Folate (B9) may help boost the effects of antidepressants. More research is needed on B vitamins and depression.
Last reviewed and updated: 16 March 2016